The present invention relates to a gas flow control system for an anesthesia apparatus of the type which operates to mix oxygen and a gaseous anesthetic such as nitrous oxide (laughing gas) and to continuously supply the gaseous mixture.
In the anesthesia apparatus of the continuous flow type, flow regulating valves are provided in an oxygen line and gaseous anesthetic line, respectively, so as to regulate the flow rate of each gaseous component. However, it is difficult to regulate the total flow rate and the proportions of the gaseous components to desired values by operating the two flow regulating valves. In recent years, a gas flow control system for an anesthesia apparatus in which the total flow rate and the mixing ratio of the gaseous components can be separately regulated has been used. However, the system has a disadvantage in that the safety during anesthetization is not ensured with failure of elements in the system.